6 1 Fire Protection

8/13/2019 6 1 Fire Protection

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Section 6.0Fire Protection

Structural steelwork

Product:Knauf FireboardFp01

Small cavity barriers

Product: Earthwool Cavity Barrier

Mezzanine floors

Product:Rocksilk FireTech Slab

Fp03

Fp04

Structural steelwork

Product:Rocksilk FireTech Slab

Fp02

Large cavity barriers

Product:Rocksilk Smoke and FireBarrier

Fp05

Refurbishment of timber

separating/internal floor

Product:Earthwool Flexible SlabFp06

Steel Duct Encasement

Product:Rocksilk Pyroduct Slab

Fp07


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66

Fire Protection6.1

Technical Advice and Support Centre 01744 766666 www.knaufinsulation.co.uk

Fire protection of structural steelFire protection design

Can be installed prior to the building being

sealed and made watertight, in all

temperature and humidity conditions thisis in contrast to paint and sprays which are

often restricted by normal UK winter

conditions, causing potential delay to

site programs

Are fast, clean, and dry to install, with

negligible dust levels, allowing other trades

to work in close proximity

Are quick and easy to check (by visual

inspection) that all relevant areas have

been protected

Are fully compatible with drylining systems

and allow easy integration with partitioning

schemes

Fire protectionAny steel section which is an element of

structure and is deemed by any of the following

regulations to require fire resistance can be

protected with a fire protection system of dense

rock mineral wool slabs or fibre reinforced

gypsum based boards.

1. The Building Regulations (England and

Wales) Approved Document B (Fire Safety)

Volumes 1 and 2 (2006)

2. The Building (Scotland) Regulations,

Technical Booklets, Section 2, 2011

3. The Building Regulations (Northern Ireland)

Technical Booklet E, 2005

4. The Building Regulations (Republic of Ireland)

Technical Guidance Document B (2006)

Structural steel requires fire protection because

it loses structural strength at temperatures that

can be rapidly reached in a building fire. Thiswill consequently have a negative impact on the

structural integrity of the building. Protecting the

structural steel from the heat of a fire will delay

the onset of this loss of strength and the possible

collapse of the building. This is essential

because it allows extra time for both the

occupants of the building to escape and fire

services to tackle the fire. It could also prevent

the actual collapse of the building minimising

insurance losses. Building Regulations covering

fire safety are concerned with the preservation

of life.

With the increasing use of structural steel inconstruction, designers need fire protection

solutions that provide a combination of fast

installation and cost-effectiveness whilst

achieving the desired finish.

Whatever the application Knauf Insulation has

a range of board products and systems to cater

for any project.

When used for the fire protection of structural

steelwork, board systems offer several

compelling advantages over site applied paint

and spray coating systems.

Board systems:

Are manufactured to factory tolerances this

enables the specifier to be certain that the

correct thickness of fire protection is being

applied, by simply checking the thickness of

materials supplied

5. Loss Prevention Council Code of Practice for

Construction of Buildings

Steel sections can include universal beams,

columns and joists (plain and castellated),

structural and rolled tees, angles, channels and

round, square or rectangular hollow sections.

BenefitsBoth rock mineral wool slabs and fibre

reinforced gypsum boards offer a number of

advantages for the fire protection of structural

steelwork that make them ideal for fast track

projects.

Rock mineral wool

Lightweight product at less than half the

weight of calcium silicate slabs rockmineral wool fire protection boards are easy

to handle and fit on site par ticularly for

overhead work

Ease of cutting and fixing: Rock mineral wool

slabs are easy to cut with either a saw or a

sharp knife, furthermore there are four fixing

methods, all involve square edge butt joints

between the boards which enables a fast and

simple system to be installed without delaying

other trades and activities

Fibre reinforced gypsum

Smooth surface only requires decorative

finishes for completion Robust and impact resistant ideal for

columns and all exposed surfaces

Easy to cut to size can be scored and

snapped to speed up cutting and reduce

dust levels

Knauf Insulation are members of

the Association for Specialist Fire

Protection, and our fire protection

products are listed in the Yellow

Book, which presents economical

methods for the fire protection of

structural steelwork to provide

compliance with Building

Regulations


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267

Fire Protection 6.1


6.

1

Fire protectionSolution optimiser and pathfinder

Fire protection

Period of fire resistance(mins)

Knauf Insulation solution

Mezzanine floorsProduct:Rocksilk FireTech Slab

See page: 280

0 mins 30 mins 60 mins 90 mins 120 mins 150 mins 180 mins 210 mins 240 mins

Fp03

Key

Find online. Visit knaufinsulation.co.uk and key in construction code to find the

most up to date information on your chosen solution.Pb01

Fp04

Large cavity barriersProduct:Rocksilk Smoke and Fire Barrier

See page: 286

Fp05

Refurbishment of timber separating/internal floorProduct:Earthwool Flexible Slab

See page: 292

Fp06

Steel Duct EncasementProduct:Rocksilk Pyroduct Slab

See page: 294

Fp07

Structural steelworkProduct:Rocksilk FireTech Slab

See page: 274

Structural steelworkProduct:Knauf Fireboard

See page: 268

Fp01

Fp02


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68

Fire Protection6.1


Fire protectionStructural steelwork

Knauf Fireboard

Typical constructionKnauf Fireboard is used in frameless

encasements. The product has been specially

developed to accept direct edge fixings.

Casings consist of Knauf Fireboard screwed or

stapled to itself at abutting corners.

For steelwork encased on all four sides, Knauf

Fireboard is fixed at each corner directly

through the material, independent of the columnor beam. For partial encasement, involving wall

or ceiling abutments, Knauf Fireboard is fixed to

light gauge steel angles.

Knauf Insulation recommend the use of Knauf

Drywall Screws, essential for fast construction,

solid fixing and tightly closed edge joints.

ProductsKnauf Fireboardis a gypsum based board

specially developed for high performance lining

and encasement, providing up to two hours of

fire protection.

Knauf Fireboard has a high quality white

smooth surface finish ideally suited as a self

finish. Its surface allows direct decoration with

most paint finishes or it can be plastered*.

Knauf Drywall Screwsare gold passivated

screws with spoon tips and hi-low threads.

Knauf Fireboard can also be installed using

proprietary staples.

*Consult plaster manufacturer prior to application of plasterfinish.

Fp01 Quick and easy to install

Dry fix system providing up to 2hours fire protection

Combined fire protection andaesthetic finish

Knauf Fireboard

Non-combustible with a Euroclass

A1 reaction to fire rating

Zero Ozone Depletion Potential (ODP)

Zero Global Warming Potential (GWP)

Edge fix the boards usingeither Knauf Drywall Screwsat maximum 150mm centresor proprietary staples at120mm centres.

Knauf Fireboard

Knauf Drywall Screws at maximum100mm centres into backing strips

Abutment angles: light gaugesteel angle provides support atsoffit and wall junctions. Fixed toadjoining soffit or section flange.

REFURBNEW BUILD


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Fire Protection 6.1


6.

1

Typical specificationKnauf Fireboard, ...mm thick, to be used to

provide fire protection to structural steelwork.

It is to be installed on beam*/column* as a

complete 4 sided*/3 sided*/2 sided*

encasement (*specifiers choice) to provide

......minutes fire protection as detailed in the

Installation section.

Alternatively, consult the NationalBuilding Specifications, Standard

version clause/clauses

K10/265

Knauf Insulation specification clauses can be

downloaded from knaufinsulation.co.uk/nbs

PerformanceFire performance

The system can provide up to 2 hours fire

protection. For precise calculation of fire

protection periods, please contact Knauf

Insulation Technical Advice and Support Centre.

Knauf Fireboard is non-combustible

to BS 476: Part 4: 1970 (1984) and Class 1

surface spread of flame to BS 476: Part 7:1997. Knauf Fireboard complies with the Class

0 requirements of the Building Regulations

when tested to BS 476: Part 6: 1989 and Part

7: 1997 and with the limited combustibility

described in the Building Regulations.

Humidity

Constant humidity over 95% or subjection to

continuous water will reduce the serviceability

of the boards.

Operating temperatures

Continuous long term exposure to temperatures

over 50C can induce a change of state which

would reduce the physical performance and

serviceability of the boards.

Health and safety

Knauf Fireboard must be installed with care.

Ensure adequate ventilation during installation,particularly when cutting boards. Avoid harsh

body contact with sharp cut edges of metal

components. Refer to Knauf Insulation Material

Safety Data Sheets and to the Health and Safety

Executive publications.

For Hp/A tables please visit

knaufinsulation.co.uk

Knauf Fireboard casing

Stagger joints by 300mm minimum

Direct edge-fixing with Knauf DrywallScrews at 200mm centres orproprietary staples at 120mm centres


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Fire Protection6.1


1 2 Hold in place thefirst 2 boards

with clamps.

3 After measuring the

size of the remaining

2 sides, cut another

two to the depth of

the column plus

twice the thickness

of the board.

4 Apply the remaining

boards, adjusting

the length of

adjoining boards to

ensure that board

joints are staggered

by at least 300mm.

5Edge-fix the boardsusing either selfdrilling Knauf

Fireboard Gripper

Screws at 200mm

centres or proprietary

staples at 120mm

centres. KnaufFireboard Gripper

Screws should

penetrate into the

casing by at least

30mm

Installation sequence

Fire protectionInstallation of column system

Partial column encasement

Assuming a typical three-sided encasement

where one of the column flanges straddles a

wall, follow the same procedure as outlined

for four-sided encasement with the following

differences:

Fix 25 x 25mm light gauge steel angles,

in continuous lengths, to either the abutting

wall face or the inner flange of the column.

Use appropriate proprietary fixings at

600mm centres

Double layer application

Install the first layer as described for either full

or partial encasement. Secure the second layer

to the first with fixings spaced as for the first

layer but avoid coincident fixing positions.

It is good practice that board joints are

staggered as with the first layer between

adjoining boards and also between the twolayers. In the case of structural steelwork,

double layer encasement will obviate the need

for joint backing strips.

Installation

Steelwork encasements must be installed in full

accordance with Knauf Insulations

recommendations and in compliance with

BS 8212: 1995 and BS 8000: Part 8: 1994.

The installation procedures outlined here relate

to normal single layer applications.

Knauf Drywall Screws

Knauf Drywall Screws should penetrate into the

casing by at least 30mm.

Four-sided column encasement

Cut two boards to the width of the column

flange. Cut another two to the depth of the

column plus twice the thickness of the board

Adjust the length of adjoining boards to

ensure that board joints are staggered by at

least 300mm

Edge-fix the boards using either Knauf

Drywall Screws at 200mm centres or

proprietary staples at 120mm centres

Cut two boards to

the width of the

column flange.


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Fire Protection 6.1


6.

1

Fire protectionInstallation of beam system

Beam encasement

Assuming a typical three-sided encasement,

where a beam is exposed directly below a level

soffit, fix light gauge steel angles to either the

adjoining soffit or the top flange of the beam.

Install continuous lengths of 25 x 25mm angle

using appropriate proprietary fixings at 600mm

centres.

Fix further lengths of 25 x 25mm angle at any

end abutment

Cut two boards to the depth of the section

plus twice the thickness of the board plus

l0mm. Screw-fix these to the angles at

150mm centres with 35mm Knauf Drywall

Screws

Cut a soffit board to the width of the steel

flange. The length of this board must differ

from the side boards to ensure adjacent

board joints are staggered by at least

300mm. Edge-fix this horizontal board to thetwo vertical boards using either self-drilling

Knauf Drywall Screws at 150mm centres or

staples at 120mm centres

Cut board off-cuts 100mm wide as joint

backing strips. Fit these, half-lapped, behind

all butt joints at the sides and soffit of the

beam fixed with Knauf Drywall Screws at

maximum 100mm centres

Double layer application

Install the first layer as described for either full

or partial encasement. Secure the second layer

to the first with fixings spaced as for the first

layer but avoid coinciding fixing positions.

It is good practice that board joints are

staggered as with the first layer between

adjoining boards and also between the two

layers. In the case of structural steelwork,

double layer encasement will obviate the need

for joint backing strips.

The second layer of boards across the webs are

fixed to the angle attached to the upper flange

using 55mm long Knauf Drywall Screws at

150mm centres and the second layer across the

bottom flange using Knauf Drywall Screws at

Installation sequence

1 Install continuous lengths of

25 x 25mm angle using

appropriate proprietary

fixings at 600mm centres, fix

further lengths of 25 x 25mm

angle at any end abutment.

2 Cut two boards to the depthof the section plus twice theboard thickness plus l0mm.

Screw-fix these to the anglesat 150mm centres with35mm Knauf Drywall

Screws.

3 Cut a soffit board to the

width of the steel flange.

The length of this board must

differ from the side boards to

ensure adjacent board joints

are staggered by at least

300mm.

Edge-fix horizontal board to

the two vertical boards using

either Knauf Fireboard

Gripper Screws at 150mm

centres or proprietary staples

at 120mm centres.

4 Cut board off-cuts 100mm

wide as joint backing strips.

Fit these, half lapped, behind

all butt joints at the sides

and soffit of the beam.

Fix with Knauf FireboardGripper Screws at maximum100mm centres.

6.

1

nominal 150mm centres, screw lengths should

be equal to the thickness of the second layer,

plus 30mm. Where two different thicknesses of

Fireboard are applied, the thicker layer is

installed first.


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Fire Protection6.1


Fire protectionApplication details for beams

25 x 25mm angle secured to top flangeof beam, or alternatively to soffit

Beam with partition abutment

Beam with wall abutment

25 x 25mm angle secured to top flange ofbeam, or alternatively to soffit

Knauf Drywall Screws at maximum100mm centres

Fireboard casing

Backing strip

10mm gap

Direct edge fixing with Knauf DrywallScrews at maximum 150mm centres orstaples at 120mm centres

C-Stud partition with standardU-Channel head track

Knauf Drywall Screws at maximum100mm centres

Fireboard casing

Direct edge fixing with KnaufFireboard Gripper Screws atmaximum 150mm centres orstaples at 120mm centres

Continuous 25 x 25mm KnaufFireboard Angle secured to substrateusing appropriate fixings

Masonry wall


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Fire Protection 6.1


6.

1

Column with partition abutment

Knauf C-Stud toggle-fixed to KnaufFireboard casing

Knauf Wallboard not fixed to this C-Stud


Continuous 25 x 25mm KnaufFireboard angle at each corner



Column with wall lining abutment


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Fire Protection6.1


Fire protectionStructural steelwork

Rocksilk FireTech Slab

Noggin of Rocksilk FireTech Slabor Rocksilk FireTech Dry Fix NogginSlab


InstallationRocksilk FireTech Slab can be used with four

types of fixing methods for the fire protection of

structural steelwork and each system has its own

performance characteristics.

Fixing methods:

Dry Fix Noggin System

Adhesive Noggin Fixing System Combination Fixing System

Welded Pin Fixing System

Typical constructionThe exposed surfaces of any steel section are

fully enclosed in Rocksilk FireTech Slab, using

any of the fixing systems shown on the following

pages.

Rocksilk FireTech Slab can be used to provide

up to 4 hours fire protection to structural steel

and cast iron columns, beams and trusses. Steel

sections may include universal beams, columns

and joists (plain and castellated), structural and

rolled tees, angles, channels and round, square

or rectangular hollow sections.

ProductRocksilk FireTech Slabis a dense rock mineral

wool slab. It is available unfaced or faced with

a bright Class 0 reinforced aluminium foil, for

applications above clean rooms, within air

plenums, or for aesthetic purposes.

Plaster manufacturers advice and guidance

should be followed regarding pre-treatment of

Rocksilk FireTech Slabs before application ofplaster finishes

Rocksilk FireTech Dry Fix Noggin Slabis an ultra

high density rock mineral wool slab used for the

noggin in the Rocksilk FireTech Dry Fix Noggin

System.

Fp02 Flexible system with four installation

methods

Maintenance free, passive system

Clean installation process withnegligible dust generation


Non-combustible with a Euroclass A1

reaction to fire rating Zero Ozone Depletion Potential (ODP)


Pig tail screws

REFURB


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Fire Protection 6.1


6.

1

Technical specificationRocksilk FireTech Slab, ...mm thick, to be

used to provide fire protection to structural

steelwork.

It is to be installed using the dry fix noggin

system*/adhesive noggin fixing system*/

combination fixing system*/welded pin

fixing system* (*specifiers choice) as

detailed in the Installation section.

Alternatively, consult the National

Building Specifications, Standard


K11/885




Rocksilk FireTech Slab is classified as

non-combustible to BS 476: Part 4:

1970(1984), Class 1 surface spread of flame

to BS 476: Part 7: 1997, and Class 0 to the

Building Regulations. Rocksilk FireTech Slab is

designed to provide up to 4 hours fire

protection to structural steelwork, thereby

satisfying the Building Regulations and

insurance demands for periods of fire

resistance.

Durability

Rocksilk FireTech Slab is rot proof, does not

sustain vermin and will not encourage the

growth of fungi, mould or bacteria.

Rocksilk FireTech Slab is odourless and

non-hygroscopic.

Rocksilk FireTech Slab is non-wicking when

tested to BS 2972: 1989: Section 12.When exposed to 90% relative humidity and

20C, Rocksilk FireTech Slab absorbs less than

0.004% of moisture.

For Hp/A tables please visit

knaufinsulation.co.uk

Noggin of Rocksilk FireTech Slab orRocksilk FireTech Dry Fix NogginSlab

Pig Tail Screws



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Fire Protection6.1


Fire protectionInstallation of Rocksilk FireTech Slab

Adhesive Noggin Fixing SystemUp to 2 hours fire protection

Attach web pieces to nogginswith pig tail screws at100mm centres.

Dry Fix Noggin SystemUp to 2 hours fire protection

Welded Pin Fixing SystemUp to 4 hours fire protection

Combination Fixing SystemUp to 3 hours fire protection

Attach web pieces tonoggins with pig tailscrews at 100mm centres.

The use of a dense rock mineral wool slab

requires no special vee cuts, drilling or

sub-frames, making it fast and easy to install.

Rock mineral wool slabs can be easily cut using

hand or power tools.

Note: Rocksilk FireTech Dry Fix Noggin Slab has a densityof 200 kg/m3.

The Combination Fixing System

Can be used to provide up to 2 hours fire

protection to all sizes of structural steelwork,

and up to 3 hours fire protection to steelwork

with section factors (Hp/A) of up to 133m-1for

columns and 143m-1for beams.

The Welded Pin Fixing System


protection to all sizes of structural steelwork,

and up to 4 hours fire protection to steelwork

with section factors (Hp/A) of up to 172m-1for

columns and 184m-1for beams.

If section factors are above 260m -1contact our

Technical Advice and Support Centre.

Alternative installation methodsThe Dry Fix Noggin System

Is a fast and efficient friction fit noggin system

that does not require adhesive. It can give up to

2 hours fire protection to BS 476: Part 21.

When installing 20, 25 and 30mm Rocksilk

FireTech Slab, noggins should be cut from a

30mm Rocksilk FireTech Dry Fix Noggin Slab.

When greater thicknesses of Rocksilk FireTech

Slab are used, the noggins are cut from a

corresponding thickness of Rocksilk FireTech Dry

Fix Noggin Slab.

The Adhesive Noggin Fixing System


protection to all sizes of structural steelwork.

100mm wide noggins ofRocksilk FireTech Dry FixNoggin Slab friction fittedbetween the flanges.

Attach flange pieces to webpieces using pig tail screwspositioned 25mm in fromeach end and at 150mmcentres.

Attach flange pieces toweb pieces using pig tailscrews positioned 25mmin from each end and at150mm centres.

100mm wide noggin ofRocksilk FireTech Slabglued into place usingsuitable adhesive

Attach the Rocksilk FireTechSlab web pieces by impalingover the welded pins andsecuring in place with 38mmspring steel washers.

Attach flange pieces to webpieces using pig tail screwsat 150mm centres.

Adhesive should be used atthe joint between subsequentweb pieces.

Attach the Rocksilk FireTechSlab web and flange piecesby impaling over the 3mmdiameter welded mild steelpins and securing in placewith 38mm spring steelwashers.

Adhesive should be used atthe joint between subsequentweb pieces.


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Fire Protection 6.1


6.

1

Adhesive noggin fixing systemNoggins are cut 100mm wide from 20mm thick

Rocksilk FireTech Slab. They should be cut to a

suitable length relative to the web size to give

a tight compression fit.

Noggins are glued top and bottom using a

typical adhesive thickness of 0.5mm and friction

fitted between the flanges at 600mm centres.

The noggins should be installed in such a way

that they are slightly 'proud' of the flange (by

about 2mm) and such that they coincide with

joints between the boards.

It is preferable to leave the noggins in position

for 4 hours to allow the adhesive to cure.

However, where this is impractical Rocksilk

FireTech Slab can still be fitted before the

adhesive cures since the noggins are essentially

friction fitted.

For web depths greater than 500mm, T-shaped

or solid noggins should be used, formed from

Rocksilk FireTech Slab, and screwed together

using pig tail screws.

Attach web pieces to noggins using pig tail

screws at 100mm centres

Solid noggin formed from one or more pieces

of Rocksilk FireTech Slab

Greaterthan

500mmFull

depth

100mm

T-shaped noggin formed from two pieces of

Rocksilk FireTech Slab joined at right angles

using pig tail screws

Insert noggins as described at 600mm

centres and if practicable leave for 4 hours

for adhesive to cure.

Cut Rocksilk FireTech Slab to size as follows:

Beams: flange pieces to dimension X, web

pieces to dimension Y + t (t = thickness of

board)

Columns: flange pieces to dimension X,web pieces to dimension Y + 2t

100mm

Greater

than

500mm

Y

X

Attach flange pieces to web pieces using pig

tail screws positioned 25mm in from each

end at 150mm centres.

Note: For flanges greater than 400mm use welded pinand spring steel washers to provide extra retention ofthe flange piece of insulation. The welded pins shouldbe located along the centre line of the flange at 300mmcentres.


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Fire Protection6.1


Fire protectionApplication details for beams

Partition abutment using a noggin fixing system

Wall abutment using a noggin fixing system

Pig tail screws at maximum100mm centres

Direct edge fixing with pig tail screws atmaximum 150mm centres

Attach flange piece to web piece byimpaling over welded pins and securingthe board to board joint with pig tailscrews at 150mm centres. Spring steelwashers are used over the welded pins toretain the insulation, any excess pinlength being trimmed off


C-Stud partition with standard U-Channel

head track

Pigtail screws at maximum 100mm centres

Attach flange piece to web piece by impalingover welded pins and securing the board toboard joint with pig tail screws at 150mmcentres. Spring steel washers are used overthe welded pins to retain the insulation, anyexcess pin length being trimmed off



Masonry wall

Rocksilk FireTech noggin


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Fire Protection 6.1


6.

1

Column with wall lining abutment

Column with partition abutment

Adhesive detail

The adhesive used for gluing Rocksilk FireTech

Slabs should be a thixotropic paste type based

on soluble solids of silicate and potassium

mixed with clay or refractory mineral filler to an

approximate ratio of 70:30 by weight.

Steelwork should ideally be dry but the

presence of condensation will merely prolong

the cure time, not weaken the bond strength.

Since only the top and bottom sur face of each

noggin is glued with a typical adhesive

thickness of 0.5mm, excellent rates of usage are

achievable.Note: Steelwork should be clean and free from grease priorto the application of adhesive.

* For further details contact our Technical Advice andSupport Centre.


Masonry wall






Pig tail screws

The spirally wound or pig tail screws are

made from 16 gauge galvanised wire and

are available from stockists. A specification

is available on request from our Technical

Advice and Support Centre.

The screws should be installed flush at 150mm

centres on board to board joints and 100mm

centres over noggins, using either power or

hand tools. There is no need to countersink thescrew heads.


16/34

80

Fire Protection6.1


Fire protectionMezzanine floors


Simple, clean and quick to install Provides up to 3 hours fire resistance System covers section factors up to

310 Hp/A - (A/V)


Non-combustible with a Euroclass A1reaction to fire rating




Rocksilk FireTech Slab is classified as

non-combustible to BS 476: Part 4: 1970

(1984). Class 1 Surface Spread of Flame to BS

476: Part 7:1977, and Class O to the

Building Regulations. Rocksilk FireTech Slab is

designed to provide up to 3 hours fire

protection to the mezzanine floor column

support system, thereby satisfying the current

Building Regulations and insurance industry fire

resistance performance standards.

Performance

Rocksilk FireTech Slab is rot proof, does notsustain vermin, will not encourage the growth of

fungi, mould or bacteria and is odourless and

non-hygroscopic.

ProductRocksilk FireTech Slab is a dense rock mineral

wool slab specifically designed for the fire

protection of structural steelwork.

Typical construction

The exposed surface of a steel section is fully

enclosed in Rocksilk FireTech Slab, using a

metal clip, snap-lock system.

Installation

The column case is pre-fabricated to suit the

specific beam or column. It is lined with Rocksilk

Firetech Slab which is pre-bonded to the steel

skin. Note that no adhesive is applied to the

joints between individual slabs. The columncase is made of galvanized or PVC coated steel

minimum 0.7mm thick. For columns, the casing

is normally supplied in two pieces with the

closing face fixed with snap-lock joints.

Three-sided encasements are secured at 300mm

centres to continuous galvanized steel angles,

or the flange of the steel section, or to the wall

or floor at 500mm nominal centres.

Alternatively the casing may be secured using

an integral lip on the casing.

Fp03


REFURB


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Fire Protection 6.1


6.

1

Technical specificationRocksilk FireTech Slab.mm thick, to be

used to provide fire protection to structural

steelwork in a mezzanine floor system.




K11/885

Knauf Insulation specification clauses can bedownloaded from knaufinsulation.co.uk/nbs

Table 1 - Mezzanine floors

Time - mins Board Thickness (mm) Hp/A

60 20 224

25 260

30 310

35 310

40 310

45 310

90 20 91

25 115

30 139

35 165

40 190

45 217

50 244

55 260

60 270

65 310

120 20 57

25 72

30 87

35 102

40 117

45 133

50 149

55 165

60 181

65 198

180 30 49

35 58

40 66

45 75

50 84

55 92

60 101

65 110


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Fire Protection6.1


Cavity barriersCavity barrier design

Design considerationsEvery building must be designed and

constructed in such a way that in the event of

an outbreak of fire within the building, the

unseen spread of fire and smoke within

concealed cavities in its structure and fabric is

inhibited. The Building Regulations require

cavity barriers to sub-divide voids if they extend

beyond certain dimensions.

In addition cavity barriers are also required tobe placed above fire resisting partitions. Both

glass and rock mineral wool products are ideal

to act as cavity barriers due to their inherent

non-combustibility.

In the case of fire stopping minor imperfections

of fit between construction elements or

components, it is acceptable to seal small gaps

with unfaced glass or rock mineral wool

products. However, for specific periods of fire

resistance in small and large voids (as required

by the Building Regulations) it is necessary to

use specific products that have been tested and

assessed to offer the required performancewhen installed in a specific way, if necessary,

using specific fixing components.

Concealed cavitiesFire and smoke spread in concealed spaces is

particularly hazardous because fire can spread

quickly throughout a building and remain

undetected by the occupants of the building.

Cavity barriers are used to sub divide

cavities and so prevent smoke and flame from

by-passing fire-resisting walls and partitions.

The maximum distance between barriers must

be appropriate to the location of each cavity.Also, due consideration must be given to the

class of surface exposed within the cavity.

Cavity barriers should achieve at least 30

minutes fire resistance, providing a minimum of

30 minutes integrity and 15 minutes insulation.

Detailed requirements are complex. For full

details about the position and spacing of cavity

fire barriers refer to the relevant sections of the

appropriate Building Regulations.

Small cavity barriersSmall voids include the cavities in external walls

and voids beneath raised access floors. Largervoids include the spaces between suspended

ceilings and soffits or roofs.

In cavities in external walls the resilient

properties of glass mineral wool mean that it

can be compression fitted, between the outer

leaf and the inner leaf or frame. The non-

combustible nature of glass mineral wool allows

it to resist the effects of fire, enabling it to

remain in place during the fire and effectively

block the transfer of fire through the cavity.

Large cavity barriersIn England, Wales and Northern Ireland, all

cavity barriers should be constructed to provide

at least 30 minutes fire resistance and 15

minutes insulation. In Scotland large cavity

barriers, which are defined as being greater

than 1m x 1m in size, must provide the same.

Fixing systemsAny product used for fire protection can only be

considered to be offering a specific period of

fire protection when it is installed in the manner

specified in the appropriate fire test report. This

includes the specification of all associated

fixings and supporting frame work.


19/34

283

Fire Protection 6.1


6.

1

DefinitionsThe following definitions are taken from

Approved Document B (Fire safety) - Volume

2: Buildings other than dwellinghouses

(2006)

Cavity barrier

A construction, other than smoke curtain,provided to close a concealed space against

penetration of smoke or flame, or provided to

restrict the movement of smoke or flame

within such a space.

Fire stop

Seal provided to close an imperfection of

fit or design tolerance between elements or

components, to restrict the passage of fire

or smoke. Any unfaced glass or rock mineral

product can be used as a fire stop.

50mm RocksilkSmoke and FireBarrier 50mm Rocksilk

Smoke andFire Barrier

50mm cavity

Suspended ceilingof 12.5mm plasterboard

30 minutes fire resistance 1 hour fire resistance

Photograph courtesy of Henley Building Systems

Small cavity barriers - to be deleted

Large cavity barriersProduct:Rocksilk Smoke and Fire BarrierSee page: 286

Fp04

Fp05

Period of fire resistance(mins)

Knauf Insulation solution 0 mins 30 mins 60 mins 90 mins 120 mins 150 mins 180 mins 210 mins 240 mins


20/34

84

Fire Protection6.1


Meets Building Regulationrequirements for fire, acoustics andparty wall bypass applications

Simple, clean and quick to install

Colour coded for easy identification

Earthwool Cavity Barrier


reaction to fire rating A+ Generic BRE Green Guide rating



Fire protectionSmall cavity barriers

Earthwool Cavity Barrier

InstallationIn vertical applications, both flanges of the

Earthwool Cavity Barrier should be fixed to the

inner leaf.

In horizontal applications, the top flange of

the polythene sleeve should be fixed to the

inner leaf.

All joints and intersections of Earthwool Cavity

Barriers should be closely butted.

Typical constructionEarthwool Cavity Barriers are engineered to

prevent the spread of smoke and fire through

walls, floors and cavities in timber frame, metal

frame and masonry buildings.

They are also suitable for reducing flanking

noise transmission in these concealed cavities.

The use of the correct size of Ear thwool Cavity

Barrier is essential. Earthwool Cavity Barriersare designed to compress to a tight fit in

cavities and in the event of fire breaking into

the cavity, Earthwool Cavity Barriers do not rely

on the polythene flanges to hold them in place,

but on their compression between the inner and

outer leaf.

It is, therefore, essential to specify the Earthwool

Cavity Barrier by reference to the actual

constructed cavity width.

ProductEarthwool Cavity Barrieris manufactured from

a continuous length of non-combustible glass

mineral wool which is compressed within a

resilient polythene sleeve incorporating two

flanges designed for ease of fixing.

The polythene sleeve is colour coded to suit a

variety of cavity widths from 50mm to 100mm

and eliminates the need for weather protectionduring installation.

The barriers are 1200mm long and can be

used in both vertical and horizontal

applications, and are available in two standard

widths (100mm and 300mm). 100mm barriers

are used for normal fire stopping and noise

reduction applications. 300mm barriers are

used where higher performance levels are

specified and at party wall/external wall cavity

junctions.

Fp04

Earthwool Cavity Barrier stapled through top flange tosheathing to fully fill the cavity

Brick outer leaf

NEW BUILD


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Fire Protection 6.1


6.

1

Technical specificationTimber frame construction

Earthwool Cavity Barrier 100mm*/300mm*

wide, coloured yellow*/ blue*/white* to be

friction fitted in the positions shown on the

drawings. Earthwool Cavity Barrier to fully fill

the depth of the cavity.

Polythene flanges to be stapled to the

timber*/sheathing board* to hold the cavity

barrier in place.

All joints and intersections of Earthwool

Cavity Barriers should be closely butted

together.




P10/420



Masonry construction

Earthwool Cavity Barrier 100mm*/ 300mm*wide, coloured yellow*/ blue*/white* to be

friction fitted in the positions shown on

the drawings.

Earthwool Cavity Barrier to fully fill the depth

of the cavity.

All joints and intersections of Earthwool

Cavity Barriers should be closely butted

together.




P10/420




Earthwool Cavity Barriers are manufactured

from glass mineral wool which has a Euroclass

A1 rating when classified in accordance with

BS EN 13501-1.

Earthwool Cavity Barriers have been tested for

fire resistance in accordance with BS 476: Par t

8: 1972 and will provide 60 minutes stability,

integrity and insulation.

Acoustic performance

Building Regulations require the use of a cavity

closer to reduce flanking noise transmission

along party wall cavities and external wall

cavities in masonry and timber frame

constructions.

Earthwool Cavity Barriers meet the generic

description for cavity closers and will therefore

ensure compliance with Part E and Robust

Details in timber frame and masonry wall

constructions.

Table 2 - Colour coding

Cavity width (mm) Colour

50-65 yellow

66-80 blue

81-100 white

Typical junction with party wall

300mm wide EarthwoolCavity Barrier - stapled tosheathing board eitherside of party wall

Earthwool Timber FrameParty Wall Slab

Earthwool FrameTherm


22/34

86

Fire Protection6.1


Fire protectionLarge cavity barrier

Rocksilk Smoke and Fire Barrier

Simple, clean and quick to install

Provides both fire and acousticperformance

Versatile, flexible and adaptablesystem


Non-combustible with a Euroclass

A1 reaction to fire rating Zero Ozone Depletion Potential (ODP)


For one hour fire resistance

Two layers of 50mm Rocksilk Smoke and Fire

Barrier, separated by a 50mm air space,

applied as a hanging curtain with wire meshto the outside, supported continuously from

above and both sides, using the fixings listed in

Table 3. At the base it is either lapped freely on

to the back of a suspended ceiling, or fixed to a

partition head.

Use foil faced Rocksilk Smoke and Fire Barrier

when the ceiling void is used as an air plenum.

Installation

See page 288 - 291 for installation details.

See Table 3 for specification of fixings and

supporting metalwork.

Typical constructionFor half an hour fire resistance

A single layer of 50mm Rocksilk Smoke and

Fire Barrier, applied as a hanging curtain,

supported continuously from above and bothsides, using the fixings listed in the Table 3.

At the base Rocksilk Smoke and Fire Barrieris

either lapped freely on to the back of a

suspended ceiling or fixed to a partition head.

Suitable for drops up to 7 metres.

ProductRocksilk Smoke and Fire Barrieris made from

rock mineral wool and formed into a flexible

mattress faced on one side with galvanised

wire mesh stitched in position.Rocksilk Smoke and Fire Barrier is also

available foil faced on one or both sides.

Rocksilk Smoke and Fire Barrier must be

installed in accordance with the specifications

detailed below and on the following pages. If

these specifications are not strictly followed the

installation cannot be deemed to offer any

specific period of fire protection.

Fixing components:

Angle: Mild steel - 50mm x 50mm x 2mm or

60mm x 40mm x 2mm

Strip: Mild steel - 40mm x 2mm

See Table 3 for suitable method of fixing angles

and strips to substrate.

Fp05

Rocksilk Smoke andFire Barrier fixed to 50mmtimber spacer

Metal angle fixed to soffit


50mm airgap

REFURB


23/34

287

Fire Protection 6.1


6.

1

Metal anglesfixed to soffit

Rocksilk Smokeand Fire Barrier

Rocksilk Smoke and Fire Barrierfixed to timber spacer

Technical specificationHalf hour cavity barrier

A single layer of 50mm Rocksilk Smoke and

Fire Barrier (*foil faced) to be installed in the

positions marked on the drawings, and fixed

in accordance with the manufacturers

recommendations. All joints either tightly

butted, overlapped, or with edges returned,

and stitched in a continuous spiral loop with

1mm diameter galvanised lacing wire.(* delete as appropriate)

One hour cavity barrier

Two layers of 50mm Rocksilk Smoke and

Fire Barrier (*foil faced), separated by a

50mm air space to be installed in the

positions marked on the drawings, and

fixed in accordance with the manufacturers

recommendations. All joints either tightly

butted, overlapped, or with edges returned,

and stitched in a continuous spiral loop with

1mm diameter galvanised lacing wire.(* delete as appropriate)




K10/545




Rocksilk Smoke and Fire Barrier is made from

rock mineral wool and is classified as non-

combustible to BS 476: Part 4: 1970. RocksilkSmoke and Fire Barrier has a Class 1 Surface

Spread of Flame to BS 476: Part 7: 1997 and

is Class 0 to the Building Regulations.

When subjected to full scale fire resistance tests

to BS 476: Part 22: 1987, a system comprising

one layer of 50mm Rocksilk Smoke and Fire

Barrier, fixed by using the components and

methods detailed on the following pages

achieved 19 minutes insulation, and retained its

integrity for 35 minutes, after which time the test

was discontinued. 50mm Rocksilk Smoke and

Fire Barrier thereby satisfies the criteria laid

down in the Building Regulations for cavitybarriers, by exceeding the minimum

requirement of 15 minutes insulation and 30

minutes integrity .

When subjected to full scale fire resistance tests

to BS 476: Part 22: 1987, a system comprising

a double layer of 50mm Rocksilk Smoke andFire Barrier, fixed by using the components and

methods detailed on the following pages,

achieved 61 minutes insulation, and retained its

integrity for 66 minutes, after which time the test

was discontinued.

A double layer of 50mm Rocksilk Smoke and

Fire Barrier thereby satisfies the criteria laid

down in the Building Regulations for one hour

cavity barriers.

These tests incorporated vertical and horizontal

joints between barriers. Fire resistance is

effective from either side of the barrier. When

tested, the wire side was exposed to the furnaceas this is the side most vulnerable to fire.


24/34

88

Fire Protection6.1


Fire protectionInstallation of half hour cavity barrier

80mm

minimum

1. Metal angle fixed to purlin 2. Fixed to purlin 3. Fixed to rib of coffered slab

4. F ixed across cof fered cei ling 5. Perimeter f ixing wi th s teel s tr ip 6. Junction with ceiling

At the ceiling junction, Rocksilk Smoke and Fire

Barrier is cut and draped on and between the

joists, and secured by fixing to steel angle,

which is itself fixed to the joists (Figure 6). For

suspended ceilings, see Figure 11.At partitions or wall heads, if a secure fixing is

available, as at soffits, Rocksilk Smoke and Fire

Barrier should be clamped with a steel strip

Two layers of 50mm Rocksilk Smoke and Fire

Barrier with a 50mm air space between them

are needed for one hour fire resistance. In

general two separate layers should be installed

back to back, each in a manner identical to that

shown for half hour fire resistance. The joints in

the two layers should be staggered and Rocksilk

Smoke and Fire Barrier returned outward at the

top and bottom. The wire reinforced sides

should be placed outward, see Figure 7.

Concrete decks

Rocksilk Smoke and Fire Barrier is clamped

between the deck and steel angle secured by

expanding bolts. If the deck is coffered it should

usually be possible to locate the cavity barrier

along one of the ribs (Figure 3). If fitted acrossthe coffering it should be clamped by steel strip,

to the steel angle which is secured to the ribs.

If the depth of coffering is less than 100mm,

Rocksilk Smoke and Fire Barrier should be

returned at the top by 300mm, to allow for

cutting at the ribs and pushed securely into the

coffering (Figure 4). If the depth of coffering is

greater than 100mm, Rocksilk Smoke and Fire

Barrier should be fixed around the coffering

using steel angle, as described above.

Alternatively, proprietary profile fillers may be

used.

The perimeter of the barrier should be securedwith steel strip (Figure 5).

InstallationThe following information and illustrations

outline typical details for the installation of large

cavity barriers. In case of uncertainty, refer to

Knauf Insulation.

Metal deck with overdeck insulation

If Rocksilk Smoke and Fire Barrier runs with the

slope of the roof, a supporting steel angle

should be fixed between purlins and the smoke

and fire barrier clamped to this with steel strip

(Figure 1). The insulation should project 80mm

beyond the strip to ensure a good seal.

If fitted across the sheeting profile, Rocksilk

Smoke and Fire Barrier should be bolted to the

purlins (Figure 2). It is returned at the top, to a

length equivalent to 3 times the profile depth, to

allow for cutting at troughs and pushing

securely into profiles. Alternatively, proprietary

profile fillers may be used.


25/34

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Fire Protection 6.1


6.

1

7. Fixed to concrete slab 8. Fixing to wall head

10. Fixing at perimeter9. Fixing to timber spacer

Partitions and wall heads

If possible, Rocksilk Smoke and Fire Barrier

should be secured with steel strip to the par tition

or wall head so as to maintain the 50mm air

space (Figure 8). If this is not possible, it should

be draped with a return of at least 150mm, or

fixed to a timber spacer which is fixed to the

partition or wall head (Figures 6 and 9).

Perimeter fixing

Rocksilk Smoke and Fire Barrier should be

secured with steel strip to the sides of the

perimeter wall, so as to maintain the 50mm air

space (Figure 10).

Fire protectionInstallation of one hour cavity barrier

Steel strip fixings: To masonry and concrete Buildex Tapcon 4H masonry anchorsTo timber Buildex HT range of fixingsTo steel angle Steel bolts

Minimum return of Rocksilk Smoke and Fire Barrier - When clamped to flat surface (vertical or horizontal)

80mm. When loose laid over horizontal surface - 150mm.

Fixing system specifications

Table 3 - Specification of angles and strips

Angle: Mild steel - 50mm x 50mm x 2mm or 60mm x 40mm x 2mm

Strip: Mild steel - 40mm x 2mm

Angle fixings to concrete decks and steel sections: angles 50 x 50 x 2mm

Fire resistance Maximum spacing of fixings (m) for the following drop heights (m)period (mins) 3 3.5 4 4.5 5 5.5 6 6.5 7

30 2 2 2 2 2 2 2 2 2

60 2 2 1.75 1.5 1.5 1 1 0.75 0.75

Key: M8bolts

M6bolts

Angle fixings to timber beams and trusses: angles 50 x 50 x 2mm

Fire resistance Maximum spacing of fixings (m) for the following drop heights (m)

period (mins) 3 3.5 4 4.5 5 5.5 6 6.5 7

30 2 2 2 2 2 2 2 2 2

60 2 2 1.75 1.5 1.5 1 1 0 .75 0.75

Key: Buildex HT screws, minimum 25mm thread penetration into timber

Buildex HT screws, minimum 40mm thread penetration into timber


26/34

90

Fire Protection6.1


Fire protectionJointing Rocksilk Smoke and Fire barrier

Suspended ceilings

With suspended ceilings where positive fixing

to wall heads or partition heads is not possible,

the weight of Rocksilk Smoke and Fire Barrier

and the stiffness of wire facing are such that it

will form an effective seal if it laps the

horizontal surface by a minimum of 150mm.

Lapped joints are only permissible where the

suspended ceiling has the same fire resistance

as the cavity barrier. Rocksilk Smoke and Fire

Barrier must be slit and fitted around any

crossing tees to eliminate gaps and ensure that

excessive loads are not transferred to the ceiling

(Figure 11).

Jointing

This section describes the approved methods for

joining adjacent pieces of Rocksilk Smoke and

Fire Barrier. The methods are applicable to both

half and one hour large cavity barriers.

12. Ver tical butt joint 13. Ver tical returned joint 14. Ver tical lap joint

500mmminimumoverlap

15. Perpendicular joint 16. Horizontal joint at a drop

Vertical and horizontal joints

Three methods of securing the joints between

adjacent pieces of Rocksilk Smoke and Fire

Barrier are approved.

Joints are tightly butted together and stitched in

a continuous spiral loop with 1mm diameter

galvanised lacing wire. The stitching should

pass through the reinforcement mesh and the

wool on each side of the butt joint at centres not

exceeding 100mm (Figure 12).

Alternatively the Rocksilk Smoke and Fire

Barrier edges are returned at least 80mm and

wired together (Figure 13), or they may be

lapped at least 100mm and wired together

(Figure 14).

Perpendicular jointsThe junction between two barriers should be

securely wired together (Figure 15) with a

return of at least 80mm.

Drops

All barriers can be used for drop heights up to

5m without additional support. For drops

between 5m and 7m it is necessary to introduce

additional supporting members in order to

support the weight of the fire barriers (Figure

16).

Services

Services which are permitted by Building

Regulations to penetrate barriers, should

be provided with collars of Rocksilk Smoke and

Fire Barrier at least 300mm long, sewn to the

main barrier and then strapped or wired so as

to avoid any possibility of gaps (Figure 17).

A half hour barrier requires a collar on

one side of the barrier. A one hour barrier

requires one collar on both sides of the barrier

system.

11. Junction with suspended ceiling


27/34

291

Fire Protection 6.1


6.

1

Penetrating steelwork

This should be provided with a collar of Rocksilk

Smoke and Fire Barrier at least 300mm long(Figure 18). The collar is fixed to the concrete or

metal deck by clamping against these surfaces

behind steel angle. The voids in the steelwork

are filled with Rocksilk Smoke and Fire Barrier

(figure 18). A half hour barrier requires a collar

on one side of the barrier. A one hour barrier

requires one collar on both of the layers of the

barrier system.

Access

Where permanent access is needed through the

barrier, a fire door and frame, rated to the

appropriate fire resistance, must be used.

Rocksilk Smoke and Fire Barrier should be fixed

securely to the frame.

300mm

minimum

17. Penetrating pipe

19. Temporary framework to ease handling

18. Penetrating steelwork

Handling

Depending on the size of the barrier and the

working space available, it is sometimes difficultto hold the material in place while top fixings

are being secured. It will be found helpful to

make a temporary prop from, e.g. slotted

angle. This may comprise a crosspiece of length

appropriate to the width of the Rocksilk Smoke

and Fire Barrier, with studs on the top which will

hook into the wire mesh of the Rocksilk Smoke

and Fire Barrier. This may be swivelled on the

top of a handle, and secured horizontally or to

the angle of the roof by an adjustable brace. It

is used to hold the Rocksilk Smoke and Fire

Barrier up, 100mm or so behind the fixing

location, while fixing is being carried out.

When fixing to a sloping deck, the top of theRocksilk Smoke and Fire Barrier should be

trimmed to the correct angle to ensure that joints

are truly vertical (Figure 19).

Following trades

The integrity of barriers must be restored if

disturbed by following trades, either duringthe building process or after completion.

This instruction should be incorporated into

the building handbook.

Fire protectionPenetrating pipes and ducts


28/34

92

Fire Protection6.1


Internal floorRefurbishment of timber separating/internal floor

Earthwool Flexible Slab

Minimum 18mm ChipboardEarthwool Flexible Slab

Support meshstapled to joists

Existing ceiling

Existing ceiling can beretained, avoiding disruptionto rooms below

Provides thermal and acousticinsulation as well as fireresistance

Meets the requirements ofApproved Document E for soundresistance of internal floors

Earthwool Flexible Slab

Non-combustible with a Euroclass A1reaction to fire rating

A+ Generic BRE Green Guide rating



Installation

After removal of the floor deck, line the voids in

the floor with 25mm wire mesh, to form a

support tray for the insulation. Staple the wire

mesh to the sides of the joists, at least 40mm up

from ceiling level.

Cut 100mm Earthwool Flexible Slabs to size

and lay onto the wire mesh support, so that

there are no gaps between the insulation andthe joists. Butt joint the insulation slabs so there

are no gaps between them.

Fix a chipboard floor deck, at least 18mm thick,

over the entire floor area.


The use of Earthwool Flexible Slab in a

suspended timber floor achieves one hour fire

resistance, whilst allowing the existing ceiling to

be retained.

To achieve one hours fire resistance:

The floor deck should be at least 18mm thick

tongued and grooved chipboard or timber

boarding The joists must be at least 200mm deep and

37mm wide

The wire mesh should be stapled to the sides

of the joists at least 40mm above the ceiling

level

Any ceiling can be used

ProductsEarthwool Flexible Slabis a multi-purpose rock

mineral wool slab designed to be friction fitted

in a wide range of acoustic, thermal and fire

resistant applications.

Introduction

Where the loft space of a two storey house is

converted into habitable accommodation, the

floor to the new rooms must have 30 minutesfire resistance over any part of the escape route

directly below. This is often the case when, for

example, the floor of the new room extends

over a landing in the stairway enclosure below.

The solution on this page provides the required

period of fire protection without having to

upgrade the existing ceiling.

Fp06REFURB


29/34

293

Fire Protection 6.1


6.

1

Typical specificationLay 100mm Earthwool Flexible Slab on

25mm chicken wire mesh, stapled to sides of

joists at least 40mm up from ceiling level and

at 600mm centres. The joists should be at

least 200 x 37mm and spaced at not more

than 600mm centres. The flooring board to

be at least 18mm thick.


Building Specifications, Standardversion clause/clauses

P10/250



Performance

Fire performance

Earthwool Flexible Slab is classified as

Euroclass A1 to BS EN 13501-1 and non-

combustible to BS 476: Part 4: 1970

(1984), Class 1 Surface Spread of Flame to BS

476: Part 7: 1997 and Class 0 to the Building

Regulations.

Acoustic

The acoustic performance of an internal floor

containing 100mm of Earthwool Flexible Slab

(and 12.50mm standard plasterboard ceiling)

will be at least 40dB and therefore, meet the

requirements of Approved Document E of the

Building Regulations.

Existing wall

Minimum 18mm chipboard

EarthwoolFlexible Slab

Wire mesh stapled to joists to providesupport for Earthwool Flexible Slab

Existing ceiling

Earthwool Flexible Slab cut and frictionfitted between last joist and wall

Typical wall floor junction


30/34

94

Fire Protection6.1


Lightweight, mineral wool has

approximately one half to one third of

the weight of traditional silicate and

vermiculite boards

Fast and simple fixing system makes the

slabs quick and easy to install

Provides excellent acoustic and thermal

performance insulation

Rocksilk Pyroduct Slab


reaction to fire rating



ProductRocksilk PyroDuct Slabis a 160 kg/m3density

rock mineral wool slab. The slabs are faced

with a bright Class O reinforced aluminium

foil, making it suitable for applications above

clean rooms, within air plenums or for aesthetic

purposes.


The exposed surfaces of steel ductwork are fullyenclosed in Rocksilk PyroDuct Slab using the

fixing system shown on the following pages.

Rocksilk PyroDuct Slab can be used to provide

up to 2 hours fire protection to steel ductwork.

InstallationRocksilk PyroDuct Slab is applied in a single

thickness, removing the need for multi layer

applications. This provides assurance of a

uniform thickness and therefore the integrity of

the system and allows for easy verification of

correct installation on site.

Individual slabs are 1200mm long and 600mm

wide making them easy to carry around site.Their lightweight nature also makes them easy

to use.The fixing system of welded pins and

square edge butt jointsgives a fast and simple

system which requires no special vee cuts,

drilling or sub-frames and also makes the slabs

fast and easy to install.

PerformanceFire

Rocksilk PyroDuct Slab is classified as

non-combustible to BS 476: Part 4: 1970

(1984), Class 1 surface spread of flame to BS

476: Part 7:1997 and Class O to the Building

Regulations.

Rocksilk PyroDuct Slab has been tested in

accordance with BS 476: 24:1987 and canprovide up to two hours fire resistance for steel

ductwork exposed to fire either inside or outside

of the duct.

Moisture resistance

Rocksilk PyroDuct Slab is non-wicking when

tested to BS 2972: 1989: Section 12. When

exposed to 90% relative humidity and 20C,

Rocksilk PyroDuct Slab absorbs less than

0.004% of moisture.

Fire protectionSteel Duct Encasement

Rocksilk Pyroduct SlabNEW BUILD REFURB

Fp07 Blockwork compartmentwall

RS33 Slab as packing

Steel angle rivetted at 150mm centres

Rocksilk Pyroduct fixed to duct

Rocksilk Pyroduct glued to wall and insulation


31/34

295

Fire Protection 6.1


6.

1

Typical specificationRocksilk PyroDuct Slab...........mm thick to be

used to provide up to 2 hours fire protection

to steel ductwork as detailed in this schedule

(specifier to state which ducts require fire

protection).

It is to be installed using the fixing system as

detailed, and at a thickness with due regard

to the duct size, orientation and period of fire

protection required.

Table 4 - Required thickness of Rocksilk PyroDuct Slab

Thickness of insulation (mm)

Period of fireresistance (hours)

Vertical ducts Horizontal ducts Kitchen extractducts

0.5 - - 45

1.0 45 45 90

2.0 90 90 -

Table 5 -Weight of slabs

Thickness(mm)

Weight(kg/m2)

45 7.20

90 14.40

WeightTable 5 shows the weight per square metre of

Rocksilk PyroDuct Slab.

Fire protection

Any vertical or horizontal, rectangular or

square steel ductwork associated with

ventilation and/or air conditioning systems,

including ducted supply and extract systems

(whether through ducts or plenums),

mechanically assisted systems and those

relying on natural convection can be

protected with Rocksilk PyroDuct Slabs to

provide the required degree of fire protection.

Achieving the required fireperformance

The required thickness of Rocksilk PyroDuct

Slab depends upon the orientation of the duct

and the period of fire resistance required.

Table 4 displays the thicknesses required for

vertical and horizontal ducts and also for

kitchen extract ducts for the commonest

periods of fire resistance.

Foil facing omitted for clarity


32/34

96

Fire Protection6.1



350m

m

X

Y

Greater

than

1000mm

350m

m

50mm

500mm

max

350m

m50mm

500mm

max

1. Weld 3mm diameter steel pins at 350mm longitudinal centres

along the centre line of the vertical sides of the ductwork.

2. Where the dimension of the vertical sides exceed 1000mm,

the steel pins should be in rows starting 50mm in from the edge

and spaced apart at a maximum of 500mm centres.

3. Weld 3mm diameter steel pins at 350mm longitudinal centres

along the horizontal surfaces of the ductwork in rows starting

50mm in from the longitudinal edge and spaced apart at a

maximum of 500mm centres.

4. Cut Rocksilk PyroDuct Slab to size as follows:

horizontal surfaces to dimension X,

vertical surfaces to dimension Y + 2t,

where t = thickness of insulation.

5. Attach the insulation by impaling over the welded pins and

securing with 38mm spring steel washers.

6. Glue all board to board joints using a thixotropic silicate

based adhesive.7. Trim off pin lengths to about 30mm excess and bend this

excess to form a right angle with the insulation.

8. Although not essential, it is good practice to offset the joints

for each surface.

6

7

8


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297

Fire Protection 6.1


6.

1


Vertical ducts

The installation detail on the previous pages for horizontal ducts is

also relevant for vertical ductwork, though the horizontal and vertical

surfaces referred to for horizontal ductwork will be the longest and

shortest surfaces respectively in vertical ductwork.

Ductwork passing through compartment

walls or floors

In accordance with The Building Regulations, when ductwork passesthrough any element of construction which has a designated period

of fire resistance, the integrity of that compartment should be

maintained. In these situations, the ductwork in the immediate vicinity

of the penetration should be stiffened as follows:

a) When the flange is within 100mm of the penetration then a50 x 50 x 3mm steel angle should be rivetted to the top edge

of the duct using a single row of rivets with washers starting50mm from the edge and at 150mm centres.

Earthwool Building Slab RS33 should be used to pack any gapbetween the main insulation and the blockwork.

120 x 90mm sections of Rocksilk Pyroduct Slab is glued to thewall and main Pyroduct insulation.

b) When the flange is greater than 100mm from the penetration,two angles should be used, fixed as described in a) above, and45mm Rocksilk Pyroduct Slab installed perpendicular to the ductat the penetration.


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Documents

6 1 Fire Protection